The present invention relates to a method for producing a piston for an internal combustion engine having at least two piston components, wherein at least two piston components are connected to one another along their corresponding joining surfaces via at least one radially or axially circumferential laser weld seam. The present invention furthermore relates to a piston producible by such a method.
Piston components are being joined more and more frequently by means of a laser welding method, and therefore this technique is becoming increasingly important. Axially or radially circumferential laser weld seams give rise to the problem that, in the region in which the start and the end of the circumferential laser weld seam overlap, the laser weld seam is not welded through, but rather has a reduced weld seam depth. This is because the power density or the energy input per unit length initially has to be increased continuously at the start of the laser welding operation (what is termed ramping up) and has to be reduced continuously toward the end of the laser welding operation (what is termed ramping down). During the ramping up and the ramping down, the laser weld seam is not welded through on account of the power density or energy input per unit length being too low then. As a consequence, microstructural defects, for example cracks, can arise upon cooling of the laser weld seam in the region of the latter which has not undergone through-welding.